120 On the Amylaceous Globules of the Floridez and Corallinee. 
a drop of sulphuric acid renders the globules violet, whilst the 
envelope remains yellow; the prolonged action of the acid dis- 
solves the granules, and all that remains of the mass is a yellow 
reticulated membrane, with circular or polygonal meshes, pro- 
duced by a fold which the membrane sends between the globules 
of the peripheral layer. A reticulated envelope of the same kind 
exists also in Halopithys ; but, the elements not having a strong 
mutual adherence, it is torn under the knife, and is only met 
with here and there in fragments carried away by the peripheral 
globules, which are inserted upon it by small pedicels. I have 
ascertained its presence in most of the species that I have inves- 
tigated ; it is therefore very frequent, if not universal. 
The amylaceous formation which is clearly defined by the two 
preceding examples, recurs with the same characters in the im- 
mense majority of the Floridez and Corallinez, as is proved by 
observations which I have already extended to more than thirty 
species belonging to twenty-five genera. ‘The differences relate 
to the mode of distribution of the globules in the tissues, and the 
form-and dimensions of the granules, which I have not as yet 
found superior to those of Halopithys, and which are sometimes 
scarcely 0-001 millim. I cannot enter here into the details of 
these observations; but they explain why certain large species, 
such as Iridea edulis, Bory, which are very rich in this sort of 
starch, may furnish a nutritive food to the poor inhabitants of 
our coasts; and at the same time they demonstrate in most of 
the Florideze and Corallineze an abundance of amylaceous matter 
which may be compared with that of the potato or the cereals. 
In the cellular Cryptogamia, starch in grains rendered blue 
by iodine accompanies chlorophyll; and its production appears 
to be correlative with the mode of life, which results from the 
functions of the green matter; where the latter is wanting no 
starch is found. The preceding observations acquire a fresh in- 
terest by showing, in a vast group of cellular plants deprived of 
chlorophyll and consequently endowed with an_ exclusively 
comburant respiration, the formation of a principle very nearly 
related to ordinary starch, but apparently not identical with it. 
Do these globules fill the vegetative cells at all periods of the 
year? and what is their part in the mode of life of these plants, 
of which so little is yet known? These are questions which I 
shall endeavour to solve as soon as circumstances will permit. 
M. Decaisne has been kind enough to verify the principal results 
of this investigation, and I beg him to accept my best thanks 
for having done so. 
